Improvement of impact strength of polyamide resins has long been of interest, for resistance to shattering or brittle breaking on impact of polyamide molded articles is a desirable feature of any molded article. Tendency to break on impact in a brittle fashion (rather than ductile fashion), is a significant limitation on the usefulness of such articles. By "ductile" is meant that cracks do not tend to propagate from the area of impact, and thus a resin having good ductility is one that is resistant to crack propagation caused by impact. The ductility of an article can be measured by notched Izod test ASTM D-256-73.
A variety of additives have been added heretofore to polyamide resins to improve strength and ductility. For example, Epstein U.S. Pat. No. 4,174,358 issued Nov. 13, 1979, describes improving impact strength and ductility by adding a selected random copolymer which adheres to the polyamide. However, the tendency of polyamides in general to break on impact in a brittle fashion increases as temperatures are lowered. Thus the use of molded articles for low temperature applications, such as winter sports equipment, automobile bumpers, and the like, is decreased. It would be desirable to have a polyamide molding blend suitable for making molded articles for low temperature applications. This invention is directed to such a molding blend.